5.9.2 Backup operations for each physical disk in the disk group

When LVM volumes are backed up, backups are taken for each physical disk in the LVM volume.

Backup operations must maintain consistency as disk groups and operations on all physical disks in a disk group must be synchronized.

Note

You should ensure that you understand the basic operations of the physical disk units that make up the LVM volume before using them. For information about basic operations, refer to "Backup operations for each physical disk that makes up the disk group" under "LVM Volume Operations" in the "ETERNUS SF AdvancedCopy Manager Operator's Guide" for the relevant operating system.

5.9.2.1 Executing backups

Synchronize all of the physical disks in the disk group when operating on them.

Perform the necessary pre- processing and post-processing for each disk group before and after backup operations, and prevent pre-processing and post-processing from being performed when each physical disk is being used.

Backups to both disk and tape

For backups to both disk and tape, if the Storage Server restarts while data is being written, the transaction volume and the backup volume will both have the same configuration, and an inconsistency with VxVM will occur when the Storage Server starts. (For cluster systems, this event will occur when the node fails over.) Accordingly, use the following procedure to create a backup log if backups are being made to both disk and tape.

Execute the pre-processing for the backup to disk.
Execute only the backup to the disk by specifying DISK for the -m option in "11.2.2.1 acmbackup (Backup command)".
Execute the post-processing for the backup to disk.
Execute the pre-processing for the tape copy.
Execute the tape copy using "11.2.2.2 acmtphistcopy (Tape copy command)".
Execute the post-processing for the tape copy.

Backups with only tape specified as the backup destination medium

The following table shows the pre- processing and post-processing that is performed before and after data is backed up to tape.

Table 5.9 Pre-processing and post-processing for backup to tape
Volume type	Pre-processing	Post-processing
Transaction volume	1. Prohibits access to all logical volumes in the disk group. 2. Unmounts any file systems in the disk group. 3. Imports the disk group.	Mounts any file system volumes that were unmounted as part of the pre-processing.

Backups to disk only

For information about backing up to disk, refer to "Backup operation for each physical disk in the disk group" under "LVM Volume Operation" in the "ETERNUS SF AdvancedCopy Manager Operator's Guide" for the relevant operating system.

5.9.2.2 Executing tape copies

Synchronize all of the physical disks in the disk group when using them.

Perform the necessary pre-processing and post-processing for each disk group before and after tape copy operations, and prevent pre- processing and post-processing from being performed when each physical disk is used.

Note

Before making tape copies, reconfigure the disk group for the backup volume. This is necessary because if a tape copy is made from a backup volume where the disk group has not been reconfigured and the Storage Server restarts during the tape copy, the transaction volume and the backup volume will both have the same configuration, and an inconsistency with VxVM will occur when the Storage Server starts. (For cluster systems, this event will occur when the node fails over.)

The following table shows the pre-processing and post-processing that is performed before and after tape copies.

Table 5.10 Pre-processing and post-processing for tape copy
Volume type	Pre-processing	Post-processing
Backup volume	1. Prohibits access to all logical volumes in the disk group 2. Unmounts any file systems in the disk group.	If necessary, mounts any volumes that were unmounted as part of the pre-processing.

5.9.2.3 Executing restorations

Synchronize all of the physical disks in the disk group when using them.

Perform the necessary pre-processing and post-processing for each disk group before and after restoration, and prevent pre-processing and post-processing from being performed when each physical disk is used.

Note

Only backup logs that have been taken using the following methods can be restored:

Executing backups
Executing tape copies

Restorations from tape

The following table shows the pre-processing and post-processing that is performed before and after restoration from tape.

Table 5.11 Pre-processing and post-processing for restoration from tape
Volume type	Pre-processing	Post-processing
Restoration destination volume	1. Prohibits access to all logical volumes in the disk group. 2. Unmounts any file systems in the disk group. 3. Deports the disk group.	1. Reconfigures the disk group. (*1) 2. Mounts any file system volumes that were unmounted as part of the pre-processing.

*1: The conditions for reconfiguring the disk group are as follows:

Table 5.12 Conditions for reconfiguring the disk group
Method for creating backup logs on the tape	Restoration destination	Reconfigure the disk group
Backup directly to tape	Transaction volumes	No
Backup directly to tape	Volumes other than transaction volumes	Yes
Tape copy	All volumes	Yes

Restorations with disk specified as the restoration source medium

For information about restoring from disks, refer to "Backup operations for each physical disk that makes up the disk group" under "LVM Volume Operations" in the "ETERNUS SF AdvancedCopy Manager Operator's Guide" for the relevant operating system.